Convert inches to mm
Enter the number of inches that you want to convert to millimeters.
How to Convert Inches to Millimeters
The inch and millimeter are both units of length. By definition, 1 inch equals exactly 25.4 millimeters. This means to convert inches to millimeters, you multiply by 25.4.
Formula
Step-by-Step Example
Convert 5 in to millimeters:
We need to convert inches to millimeters
Since 1 in = 25.4 mm, multiply by 25.4
5 × 25.4 = 127
5 in = 127 mm
Inch to Millimeter Conversion Table
Quick reference table for common inch to millimeter conversions. Click any value for detailed calculation.
| Inches (in) | Millimeters (mm) |
|---|---|
| 1 in | 25.4 mm |
| 2 in | 50.8 mm |
| 5 in | 127 mm |
| 10 in | 254 mm |
| 15 in | 381 mm |
| 20 in | 508 mm |
| 25 in | 635 mm |
| 50 in | 1270 mm |
| 100 in | 2540 mm |
About These Units
Inch (in)
An inch (in or ") is an imperial unit equal to 1/12 foot or exactly 2.54 centimeters. Inches measure screen sizes (TVs, monitors, phones), paper dimensions, rainfall, and small objects in the US, UK, and Canada. There are 25.4 millimeters in one inch.
Millimeter (mm)
A millimeter (mm) is a metric unit of length equal to 1/1000 of a meter or 0.03937 inches. Millimeters are essential for precision measurements in engineering, manufacturing, medical imaging, and rainfall measurements. There are 25.4 mm in one inch.
Frequently Asked Questions
How do I convert inches to millimeters?
To convert inches to millimeters, multiply the value by 25.4. For example, 10 in = 254 mm.
How many millimeters are in 1 inch?
1 inch equals 25.4 millimeters.
What is the formula for inches to millimeters?
The formula is: mm = in × 25.4.